Issue #3372089 by larowlan, lauriii: Remove field_ui_theme_suggestions_form_element_alter in favor of specifying the theme wrapper on the element

core/modules/field_ui/field_ui.module

@@ -68,9 +68,7 @@ function field_ui_theme() {
     // include default form element classes.
     'form_element__new_storage_type' => [
       'base hook' => 'form_element',
-      'variables' => [
-        'variant' => NULL,
-      ],
+      'render element' => 'element',
     ],
   ];
 }
@@ -227,25 +225,6 @@ function field_ui_form_field_ui_field_storage_add_form_alter(array &$form) {
   $form['add']['new_storage_type']['#options'][$optgroup]['entity_reference'] = t('Other…');
 }
 
-/**
- * Implements hook_theme_suggestions_HOOK_alter().
- */
-function field_ui_theme_suggestions_form_element_alter(array &$suggestions, array $variables, $hook) {
-  // Create a template suggestions for radio items in the add field form.
-  if ($variables['element']['#type'] !== 'radio' || !isset($variables['element']['#name'])) {
-    return;
-  }
-  $names = [
-    'new_storage_type',
-    'group_field_options_wrapper',
-  ];
-  if (!in_array($variables['element']['#name'], $names, TRUE)) {
-    return;
-  }
-
-  $suggestions[] = $hook . '__new_storage_type';
-}
-
 /**
  * Implements hook_preprocess_HOOK().
  */

core/modules/field_ui/src/Form/FieldStorageAddForm.php

@@ -215,6 +215,7 @@ class FieldStorageAddForm extends FormBase {
           '#parents' => ['new_storage_type'],
           '#title_display' => 'before',
           '#description_display' => 'before',
+          '#theme_wrappers' => ['form_element__new_storage_type'],
           // If it is a category, set return value as the category label,
           // otherwise, set it as the field type id.
           '#return_value' => $display_as_group ? $val['category'] : $val['unique_identifier'],
@@ -284,6 +285,7 @@ class FieldStorageAddForm extends FormBase {
         foreach ($unique_definitions[$selected_field_type] as $option_key => $option) {
           $radio_element = [
             '#type' => 'radio',
+            '#theme_wrappers' => ['form_element__new_storage_type'],
             '#title' => $option['label']->render(),
             '#description' => [
               '#theme' => 'item_list',